Detection of dioxin-like activity in dielectric fluids by an epithelial cell culture bioassay

Abstract Studies were performed to determine the feasibility of using an in vitro bioassay to detect the conversion of polychlorinated biphenyls (PCBs) to polychlorinated dibenzofurans (PCDFs) in Aroclor-based dielectric fluids, which were subjected to pyrolysis or combustion. The bioassay is based on alterations in growth and cellular morphology of epithelial cell cultures, which are considered related to PCDF-induced chloracne in humans. Pyrolysis of Aroclor 1254 at 550°C for 15 min results in a 100-fold increase in the bioassay activity, which is correlated to enhanced PCDF levels, as determined by gas chromatographic/mass spectrometric analysis. Results of testing of six chemically characterized, inservice transformer fluids, demonstrated that the bioassay is potentially useful for screening of used dielectric fluids and other substances for Dioxin-like aggregate activity.